@joynow/prettier-plugin-svelte

Prettier for Svelte 3 components

Format your Svelte components using Prettier.

Features

• Format your HTML, CSS, and JavaScript using prettier
• Format Svelte syntax, e.g. each loops, if statements, await blocks, etc.
• Format the JavaScript expressions embedded in the Svelte syntax
  • e.g. expressions inside of {}, event bindings on:click="", and more

How to use in VS Code and Atom

This plugin comes with Svelte for VS Code and Svelte for Atom so just install the extension for your favorite editor and enjoy.

If you want to customize some formatting behavior, see section "Options" below.

Some of the extensions let you define options through extension-specific configuration. These settings are ignored however if there's any configuration file (.prettierrc for example) present.

How to install manually

npm i --save-dev prettier-plugin-svelte prettier

How to use (CLI)

Install prettier and prettier-plugin-svelte as dev dependencies in your project.

Then format your code using Prettier CLI. You may need to add --plugin-search-dir=.

prettier --write --plugin-search-dir=. ./**/*.html

If you want to customize some formatting behavior, see section "Options" below.

Options

Configurations are optional

Make a .prettierrc file in your project directory and add your preferred options to configure Prettier. When using Prettier through the CLI, you can also pass options through CLI flags, but a .prettierrc file is recommended.

Svelte Sort Order

Sort order for svelte:options, scripts, markup, and styles.

Format: join the keywords options, scripts, markup, styles with a - in the order you want.

Default	CLI Override	API Override
options-scripts-markup-styles	--svelte-sort-order <string>	svelteSortOrder: <string>

The options order option only exists since version 2. If you use version 1 of prettier-plugin-svelte, omit that option (so for example only write scripts-markup-styles).

Svelte Strict Mode

More strict HTML syntax: less self-closed tags, quotes in attributes, no attribute shorthand (overrules svelteAllowShorthand).

Example:

<!-- svelteStrictMode: true -->
<div foo="{bar}"></div>

<!-- svelteStrictMode: false -->
<div foo={bar} />

Default	CLI Override	API Override
false	--svelte-strict-mode <bool>	svelteStrictMode: <bool>

Svelte Allow Shorthand

Option to enable/disable component attribute shorthand if attribute name and expression are same.

Example:

<!-- allowShorthand: true -->
<input type="text" {value} />

<!-- allowShorthand: false -->
<input type="text" value={value} />

Default	CLI Override	API Override
true	--svelte-allow-shorthand <bool>	svelteAllowShorthand: <bool>

Svelte Bracket New Line

Deprecated since 2.5.0. Use Prettier 2.4.0 and bracketSameLine instead.

Put the > of a multiline element on a new line. Roughly the Svelte equivalent of the jsxBracketSameLine rule. Setting this to false will have no effect for whitespace-sensitive tags (inline elements) when there's no whitespace between the > of the start tag and the inner content, or when there's no whitespace after the > of the end tag. You can read more about HTML whitespace sensitivity here. You can adjust whitespace sensitivity through this setting.

Example:

<!-- before formatting -->
<span><div>foo</div><span>bar</span></span>
<div pretend break>content</div>

<!-- after formatting, svelteBracketNewLine true -->
<span
    ><div>foo</div>
    <span>bar</span></span
>
<div
     pretend
     break
>
    content
</div>

<!-- after formatting, svelteBracketNewLine false -->
<span
    ><div>foo</div>
    <span>bar</span></span>
<div
     pretend
     break>
    content
</div>

Default	CLI Override	API Override
true	--svelte-bracket-new-line <bool>	svelteBracketNewLine: <bool>

Svelte Indent Script And Style

Whether or not to indent the code inside <script> and <style> tags in Svelte files. This saves an indentation level, but might break code folding in your editor.

Default	CLI Override	API Override
true	--svelte-indent-script-and-style <bool>	svelteIndentScriptAndStyle: <bool>

.prettierrc example

{
  "svelteSortOrder" : "options-styles-scripts-markup",
  "svelteStrictMode": true,
  "svelteBracketNewLine": false,
  "svelteAllowShorthand": false,
  "svelteIndentScriptAndStyle": false
}

Usage with Tailwind Prettier Plugin

There's a Tailwind Prettier Plugin to format classes in a certain way. This plugin bundles prettier-plugin-svelte, so if you want to use the Tailwind plugin, uninstall prettier-plugin-svelte and use the Tailwind plugin instead. If you are using VS Code, make sure to have the Prettier extension installed and switch the default formatter for Svelte files to it.

More info: https://github.com/tailwindlabs/prettier-plugin-tailwindcss#compatibility-with-other-prettier-plugins

FAQ

Why is the closing or opening tag (> or <) hugging the inner tag or text?

If you are wondering why this code

<span><span>assume very long text</span></span>

becomes this

<span
      ><span>assume very long text</span
    ></span
>

it's because of whitespsace sensitivity. For inline elements (span, a, etc) it makes a difference when rendered if there's a space (or newline) between them. Since we don't know if your slot inside your Svelte component is surrounded by inline elements, Svelte components are treated as such, too. You can adjust this whitespace sensitivity through this setting. You can read more about HTML whitespace sensitivity here.